This invention relates to the reshaping of freehand drawn lines and shapes in an electronic document. More particularly the invention relates to automatically straightening line segments in a line and to reshaping closed-line shapes.
With the increasing use of stylus and touch sensitive screens to input lines and images into a computer, one problem that has arisen is the poor quality of the freehand drawn lines and shapes, and the resulting difficulty in interpreting the user input. Further there are a number of other difficulties in processing freehand sketched lines and images. First, it is difficult to determine whether a freehand sketched line, that would typically not be straight, is a multiple-segment line with successive segments at angles to each other (a polyline) or is a single straight segment. Further, polysided shapes are often so irregular that the freehand drawing looks sloppy at best and may not be understandable at all by user or computer. The problem then is how to improve a freehand sketch of a line or shape so it may be more clearly understood by the user or any computing system processing the drawings.
In accordance with this invention the above and other problems have been solved by first recognizing freehand drawn lines and shapes and generating a line made up of sequential straight line segments for the freehand drawn line when the line does not form a closed line and generating a multiple straight-line-segment shape when the line forms a closed line. A basic shape is selected from reference ideal shapes as the basic shape of the multiple segment shape. The basic shape is adjusted to provide a specific shape as an improved shape for the freehand drawn shape.
The recognition of the freehand drawn lines and shapes is accomplished by comparing source segments of a source freehand drawn line to a straight line and substituting a straight line segment for a source segment if the deviation between the source segment and the straight line is below a predetermined value. Sequential source segments of a source freehand drawn line are evaluated to determine if they are an angle segment. A segment pair of sequential source line segments are defined as an angle segment having two straight line segments intersecting at a common end point if both source segments of the segment pair are within a predetermined deviation value from a straight line. The straight line segments and angle segments are combined to form a multiple segment line if the line does not close on itself and a multiple segment shape if the line does close on itself.
The invention may be implemented as a computer process, a computing system or as an article of manufacture such as a computer program product or computer readable media. The computer program product may be a computer storage media readable by a computer system and encoding a computer program of instructions for executing a computer process. The computer program product may also be a propagated signal on a carrier readable by a computing system and encoding a computer program of instructions for executing a computer process.
These and various other features as well as advantages, which characterize the present invention, will be apparent from a reading of the following detailed description and a review of the associated drawings.